Correlations in two-component log-gas systems

A systematic study of the properties of particle and charge correlation functions in the two-dimensional Coulomb gas confined to a one-dimensional domain is undertaken. Two versions of this system are considered: one in which the positive and negative charges are constrained to alternate in sign along the line, and the other where there is no charge ordering constraint. Both systems undergo a zero-density Kosterlitz-Thouless type transition as the dimensionless coupling $\Gamma := q^2 / kT$ is varied through $\Gamma = 2$. In the charge ordered system we use a perturbation technique to establish an $O(1/r^4)$ decay of the two-body correlations in the high temperature limit. For $\Gamma \rightarrow 2^+$, the low-fugacity expansion of the asymptotic charge-charge correlation can be resummed to all orders in the fugacity. The resummation leads to the Kosterlitz renormalization equations.Comment: 39 pages, 5 figures not included, Latex, to appear J. Stat. Phys. Shortened version of abstract belo

Kidney transplantation in childhood: mental health and quality of life of children and caregivers

Our objective was to assess the mental health and health-related quality of life (HRQOL) in children and their parents after renal transplantation (TX) compared to healthy controls and children with acute lymphoblastic leukemia (ALL) and to identify possible health status variables associated with impaired mental health and HRQOL. Thirty-eight TX children with a median age of 13 (range 3–19) years were investigated. Mental health was assessed by the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales and the Strength and Difficulties Questionnaire (SDQ-20). Each mother’s own mental health and QOL were assessed by the General Health Questionnaire (GHQ-30) and the Quality of Life Scale (QOLS). Forty children with ALL [median age 11 (8.5–15.4) years] and 42 healthy children [median age 11 (8.9– 15) years] served as controls. Treadmill exercise results from 22 of the 38 patients were included in the analysis. TX children showed significantly higher levels of mental health problems and lower HRQOL at 2 to 16 years after transplantation compared to both control groups. Body mass index and maximal oxygen uptake (n = 22/38) were significant predictors of child mental health (SDQ) and child QOL (PedsQL), respectively. Based on these results, we suggest that rehabilitation after TX should include a focus on physical activity and QOL to reduce interconnected physical and psychological morbidity in kidney TX children

Radioactivity, environment and the public: Building an index of environmental radioactivity

In the end of 2007, ASN launched an internal reflexion on the information of the public on the radioactivity levels in the environment. The aim was to develop a radioactivity environment scale or index, based on existing scales used for air pollution. After the presentation of a demonstration model by ASN in 2008 to HCTISN, a working group (WG) was constituted in the beginning of 2009 by ASN with stakeholders with the approval in March 2009 of the goals to be reached by this index: a communication instrument to qualify the information of the radioactivity levels in the environment, consistent with INES, particularly when sanitary consequences may occur, easy to elaborate from the available measured values of radioactivity and always usable for any location, independently of an incidental or accidental situation

Développement d'un piégeur passif pour la surveillance du tritium atmosphérique

Le développement d'un dispositif passif de prélèvement du tritium atmosphérique a été initié en 2012 pour optimiser les moyens de surveillance régulière de l'environnement en complémentarité avec les dispositifs existants (barboteur, condenseur). Le concept devait répondre à des contraintes de simplicité de mise en œuvre sur le terrain (pas d'apport en énergie, compacité…) et présenter des performances équivalentes aux meilleurs dispositifs disponibles actuellement sur le marché. L'étude a porté sur le piégeage du tritium sous forme de vapeur d'eau dans l'air (HTO). Elle a intégré le design du piège de terrain, la sélection des matériaux utilisés, le développement d'une chambre à atmosphère contrôlée et d'un système de désorption des pièges passifs pour des analyses en laboratoire. Une série de tests de qualifications dans des conditions de laboratoire puis dans l'environnement a été menée. Les résultats obtenus avec ces prélèvements passifs démontrent une très bonne concordance avec ceux obtenus avec les moyens utilisés habituellement en routine (barboteurs, condenseurs) sur une plage d'activité couvrant le bruit de fond naturel jusqu'à des niveaux identiques à ceux des rejets gazeux des installations nucléaires. Ils démontrent en outre le potentiel offert par ce nouveau dispositif pour une utilisation opérationnelle en surveillance des rejets, de l'environnement mais aussi pour des études spécifiques de type cartographique ou une utilisation en situation de crise

Decision threshold associated with multiple measurements. Application to the synthesis of the environment monitoring results

When the sample activity is measured for various reasons several times, then with each measurement can be associated an individual decision threshold and limit of detection. Each measurement can be analyzed through its own decision threshold. The whole measurements can sometimes present contradictory results, some measurements being lower than the decision threshold and other higher. The problem then arises to build a decision threshold and a detection limit taking into account all the individual results, and to decide if the radioactivity is finally detected or not. It is interesting to note that it is possible sometimes that the decision threshold taking account all results makes it possible to decide that the radioactivity is present whereas the totality of the individual results are negative in terms of individual decision threshold. The purpose of this article is to show how these thresholds and these coherent limits cumulated can be determined in way according to the experimental conditions. In a general way a rigorous method of cumulating makes it possible to systematically decrease the decision threshold and limit of detection in terms of activity. This approach has interesting applications in gamma spectrometry with multi-emitters, discharge or periodical environmental measurements. On the basis of measurements realized by the IRSN within the framework of the national monitoring of the environment, we will see the potential impact of these methods on the final assessments